The present invention relates generally to sand blasting apparatus and methods which are especially well suited for directing a spray of relatively fine grit particulates (e.g., sand) toward surfaces that are difficult to access (e.g., pipe surfaces located immediately adjacent a process vessel wall).
The technique of abrading a surface by directing a pressurized spray of grit particulates thereagainst is colloquially known as xe2x80x9csand blastingxe2x80x9d. Sand blasting is a notoriously well known technique for removing materials from rigid surfaces. Essentially, sand blasting effectively xe2x80x9ccleansxe2x80x9d undesired materials accumulated on a surface by means of the abrasive action caused by a high pressure stream of grit particulates directed against the surface. Thus, sand blasting is particularly effective for use against mortar or metal surfaces prior to application of coating materials.
There are a variety of sand blasting apparatus to accomplish a variety of surfaces. Oftentimes, however, conventional sand blasting apparatus cannot be employed effectively to abrade surfaces with relatively small clearance between the surface to be sand blasted and an adjacent rigid structure. For example, it is sometimes necessary to remove scale from pipes within process equipment, such as coker units employed in the manufacture of hydrocarbon products. One side of such pipes in conventional coker units (especially so-called xe2x80x9csingle firedxe2x80x9d coker units), however, may be located physically close to the refractory wall of the vessel thereby making scale removal by means of sand blasting difficult, if not impossible.
It would therefore be highly desirable if apparatus and methods were available which would allow sand blasting of surfaces that are difficult to access. It is toward providing such apparatus and methods that the present invention is directed.
Broadly, the present invention is directed to apparatus and methods whereby difficulty accessible sites of a structure may be sand-blasted. More specifically, according to an aspect of the present invention, sand-blasting systems are provide which include a source of pressurized grit particulates, a nozzle for discharging a spray of the pressurized grit particulates, and a flexible supply hose connecting the source of the grit particulates to the nozzle so as to supply the grit particulates from the source thereof to the nozzle. Important to the present invention, a sand-blasting fixture supports the nozzle and a distal portion of the supply hose in such a manner that the spray of grit particulates may be directed against the difficultly accessible site of the structure.
In preferred forms, the fixture includes rigid proximal and distal support tubes joined to one another so as to establish an angle therebetween, and a rigid back-lash support member extending outwardly from the distal support tube. In such a manner, the distal portion of the supply hose is movably supported within the proximal and distal support tubes such that the nozzle positioned adjacent to the back-lash support member may be adjustable by means of the distal portion of the supply hose being further advanced into or retracted from within the proximal and distal support tubes. A clamp member is most preferably provided to positionally fix the nozzle to the back-lash support member.
These as well as other aspects and advantages of the present invention will become more clear after careful consideration is given to the following detailed description of the preferred exemplary embodiment thereof which follows.